含ADN推进剂的能量特性及综合性能

为研究含二硝酰胺铵(ADN)推进剂的能量、安全、贮存及燃烧性能,根据最小自由能原理计算了含ADN推进剂的能量特性参数,采用密闭爆发器及靶线法测试其爆热及燃速,并对其吸湿性及感度进行了研究。结果表明,含ADN/Al/HMX、ADN/Al/CL-20、ADN/AlH3/HMX和ADN/AlH3/CL-20推进剂的标准理论比冲分别为2 675~2 685、2 677~2 686、2 801~2 810和2 803~2 812N·s·kg-1,采用硝酸酯增塑的惰性聚醚黏合剂体系可制备出固化正常、结构致密的含ADN推进剂。随着推进剂配方中ADN含量的增加,推进剂的爆热、吸湿性、燃速和压强指数增大,摩擦感度和撞击撞击提高,密度略有降低。     

ADN及其固体推进剂燃烧特性的研究进展

系统介绍了二硝酰胺铵(ADN)燃烧的最新研究动态,综述了国内外近年来报道的ADN燃烧时发生的物理化学变化、ADN燃烧机理、催化剂/ADN混合物燃烧性能以及ADN基固体推进剂燃烧特性的最新研究进展。首先指出了ADN的燃烧主要受凝聚相反应控制,ADN燃烧波结构包括固相层、泡沫层(包括固-气和液-气)和气相层;其次,总结了ADN基固体推进剂燃烧特性的研究现状,对现有研究中存在的局限性进行了分析;最后,指出继续开发适用于ADN基固体推进剂的新型燃烧催化剂是今后研究的重点方向之一。另外,随着非异氰酸酯固化体系在ADN基固体推进剂中的应用,需进一步加深ADN基固体推进剂燃烧性能的研究,尤其是三唑环的引入对ADN热分解及推进剂中其他组分热分解的影响。     

二硝酰胺铵推进剂的能量特性

二硝 (基 )酰胺 (基 )铵 (ADN)是一种新型稳定的高能无机氧化剂 ,其单元推进剂的比冲为 2 0 0 3.2 Ns/kg,燃烧温度为 2 10 0 K,用ADN取代丁羟复合固体推进剂中的高氯酸铵 (AP) ,比冲可提高 10 4.5 Ns/kg,与 GAP组成的无烟推进剂比冲可达 2 6 0 7Ns/kg,由GAP/ADN/RDX组成的无烟推进剂 ,最高比冲为 2 6 30 Ns/kg.     

可用于替代肼的2种绿色单组元液体推进剂HAN、ADN

给出了绿色单组元液体推进剂的定义.从推进性能、毒性、环境友好性方面讨论了硝酸羟胺(HAN)和二硝酰胺铵(ADN)基单组元液体推进剂相比肼单组元推进剂的优势.介绍了这两种单元推进剂的国外最新应用情况.     

混酸法合成ADN的分离纯化工艺研究

二硝酰胺铵（ADN）是一种高能高燃速和不含氯元素的新型氧化剂,混酸法合成ADN时会生成大量的无机盐副产物,采用活性炭吸附的方法可以对ADN进行有效的分离纯化。对活性炭的种类、吸附溶剂的种类、解吸溶剂的种类、吸附浓度、吸附方式进行了研究,并确定了较佳的工艺条件,制备了质量分数达99．5％以上的ADN。     

活性炭吸附ADN过程的动力学与热力学

通过不同温度下的静态吸附实验,研究了活性炭吸附ADN的动力学和热力学特征。以吸附量和解吸率为指标对3种活性炭(AC、BC、CC)进行对比研究,利用准一级动力学模型、准二级动力学模型和颗粒内扩散模型考察了ADN的吸附动力学,并利用Langmuir和Freundlich吸附等温模型描述吸附热力学行为。结果表明,活性炭AC是分离ADN的理想吸附剂,3种活性炭吸附ADN的动力学曲线更符合准二级动力学模型;Freundlich模型描述活性炭AC对ADN的吸附规律更为合适,该吸附△G0,△S0,吸附过程可自发进行;不同吸附量下的△H0,吸附为吸热过程。     

含1,1–二氨基–2,2–二硝基乙烯推进剂的能量特性参数计算研究

利用国军标方法及CAD系统软件,在标准条件(pc∶p0=70∶1)下,计算了含1,1-二氨基-2,2-二硝基乙烯(FOX-7)的各类推进剂的能量特性参数,分析了氧化剂(AP、RDX、CL-20)及黏合剂(HTPB、PET、GAP、PBAMO)等成分对FOX-7推进剂能量特性的影响。结果表明,将AP加入HTPB/FOX-7推进剂配方中取代FOX-7可有效改善氧条件,有利于推进剂能量的提高。在黏合剂含量较低(质量分数<8%)的推进剂体系中,使用惰性黏合剂有利于提高推进剂的能量;而在黏合剂含量较高(质量分数>10%)的推进剂体系中,使用含能黏合剂提高推进剂能量的幅度优于惰性黏合剂,且GAP优于PBAMO。用FOX-7取代NEPE推进剂中的AP,推进剂最大理论比冲可达2 567 N.s/kg。由GAP/FOX-7/RDX组成的无烟推进剂,在很宽的范围内都可以达到2 400 N.s/kg以上的理论比冲值。     

Zr/Al基高能固体推进剂的能量特性分析

为探究锆粉含量对高能推进剂能量特性的影响规律,利用热力学计算软件CEA分析了不同锆含量的Zr/Al基NEPE推进剂和Zr/Al基叠氮高能推进剂的能量特性;通过计算这两种推进剂的燃烧温度、密度、比冲和密度比冲等能量特性参数,得到了锆含量对推进剂能量特性参数的影响规律,并将结果与ZrH_2/Al基高能推进剂进行对比分析。结果表明,随着Zr含量增加,NEPE推进剂的燃烧温度和比冲均呈下降趋势,密度比冲持续上升,但考虑推进剂的能量特性和高燃温条件下的不稳定燃烧,认为在推进剂中添加质量分数3%～5%的Zr粉较适中;随着Zr含量增加,叠氮高能推进剂的燃烧温度和比冲呈现先增后减的趋势,且分别在Zr粉质量分数为6%和3%左右达到最大值,推进剂密度比冲持续上升。ZrH_2/Al基推进剂的能量性能低于Zr/Al基推进剂的。     

含硝仿肼的固体推进剂能量特性研究

研究了三种含硝仿肼 (HNF)的固体推进剂 HNF/GAP/A1、NC/NG/HNF/RDX、NC/NG/HNF/RDX/Al的能量特性 ,绘制了等性能三角图 ,可形象、直观地看出这类推进剂的比冲、燃烧温度与配方组分之间的关系     

二硝酰胺铵的结晶控制研究

通过溶剂—非溶剂重结晶法制备了短棒状的二硝酰胺铵(ADN),采用扫描电镜(SEM)、激光粒度仪分析了加料方式、超声波振荡、晶体生长控制剂等因素在重结晶过程中对ADN晶体形貌和粒度的影响。结果表明:超声波辅助沉积技术可明显改善ADN的晶体形貌和防止晶体团聚;采用无机硝酸盐为晶形控制剂可显著减小ADN晶体的长径比;经晶形控制后,ADN晶体的形貌呈现规则化,表面光滑无棱角,颗粒大小更加均匀、平均粒径为(80±1)μm,粒度分布范围变窄、可控制在33～142μm;按GJB 772A—97测试的摩擦感度由16%降低至4%,撞击感度提高了4.2 J,安全性能明显优于最初样品,吸湿性也得到明显改善。     

Insensitive munitions (IM) and combustion characteristics of GAP/AN composite propellants

Sensitivities to the ballistic shock and burn rate characteristics of GAP/AN composite propellants were investigated. Nitrate esters, such as TMETN and NC, were very effective ballistic modifier that provided useable burn rate and pressure rate exponent for minimum signature propellant based on AN. Their low temperature mechanical properties became less sensitive to the temperatures with nitrate esters. Dioctyl adipate platicized propellant showed excellent mechanical properties at operational temperature ranges. The primary initiation mechanism of card gap test was not dominated by the mechanical properties. Although NC significantly increased the critical shock pressure, 14.8% HMX and AP were less effective to the sensitivities. GAP/AN propellants showed excellent IM characteristics to the ballistic shock applied here.     

Thermal decomposition of GAP and GAP-based double-base propellants

This paper reports the thermal decomposition pattern of GAP and GAP-containing double-base (DB) compositions. Dynamic and isothermal TGA reveal a two-stage decomposition process for GAP. At temperatures below 200°C reactant-product interface diffusion, while at higher temperatures nucleation-based diffusion processes appear to be operative. Inclusion of GAP resulted in a drop in temperature for the onset of freeradical reaction.Explosives Research and Development Laboratory, Pune 411 008, India. Department of Chemistry, University of Poona, India. Published in Fizika Goreniya i Vzryva, Vol. 29, No. 3, pp. 27–31, May–June, 1993.     

Laser-induced ignition of solid propellants for gas generators

An experimental study was conducted to evaluate the ignitibility of a family of potential gas-generator solid propellants under different CO₂ laser heat fluxes and chamber operating conditions. Six types of solid propellant were tested: one baseline and five variations. The ingredients of the baseline propellant were ammonium nitrate, guanidine nitrate, potassium nitrate, and polyvinyl alcohol. The other five propellant variations were obtained by adding different amounts of carbon black, ammonium perchlorate, RDX, and triamino guanidine nitrate to the baseline formulation. The propellants were tested in a high-pressure windowed strand burner, which was pressurized with either air or argon purge gases. Propellant ignition was accomplished by a 50-W CO₂ laser. The ignition delay times of the propellants were measured at pressures of 1 and 69 atm using high-speed video cameras. In this paper, the test results and comparison of the ignition and combustion characteristics of these propellants were presented.     

Energy balances and uniaxial failure of solid propellants

A simple test procedure was used to determine the total damage in a propellant that accumulates during a tensile test from 0% strain to failure. Damage energies of two propellants were measured at various temperatures and straining rates, and Williams-Landel-Ferry shift procedures were applied to the results. The reduced master curves for the total damage energy at failure are used to compare the failure behavior of the two propellants.     

Thermal structural damage and thermal decomposition characterization of GAP propellants with nitrate ester plasticizers

GAP and nitrate ester compounds are introduced into the solid propellant formulation as energetic binders and energetic plasticizing agents, respectively, to further enhance the energy level of solid propellants. However, under abnormal thermal conditions, various components within GAP propellants, especially nitrate ester plasticizers, can collectively result in the generation of a large number of voids within the propellant due to factors such as thermal stress and slow component decomposition. This phenomenon can impact the safety of solid rocket engines, necessitating research into their thermal decomposition processes and thermal damage structures. In this study, the thermal decomposition characteristics and gas products of GAP propellants with different nitrate ester plasticizer formulations were investigated using DSC-TG and FT-IR. The damage structure of GAP propellants heated under unignited conditions was studied through Micro-CT, examining the influence of heating conditions and nitrate ester plasticizers on the thermal damage structure of GAP propellants. During heating, the thermal damage structure of GAP propellants was found to include voids generated within the GAP binder and cracks at the interface between the GAP binder and particles, with nitroglycerin as a plasticizer exacerbating the thermal damage of GAP propellants (about 2.2–2.9 times).     

温度和拉伸速率对硝酸酯增塑的GAP/CL–20固体推进剂拉伸力学行为的影响

通过单轴拉伸实验获得了聚叠氮缩水甘油醚(GAP)/六硝基六氮杂异伍兹烷(CL–20)推进剂在–40~70℃和0.5~5 000 mm/min的拉伸速率(ν)下的应力–应变曲线。GAP/CL–20推进剂的力学性能呈现明显的温度(t)和拉伸效应,温度和拉伸的耦合作用,使推进剂的力学性能发生显著的变化。初始弹性模量和最大拉伸强度σm随t的降低与ν的升高逐渐增加,σm与lnν呈线性关系。与模量和强度相比,最大伸长率εm和断裂伸长率εb的变化规律较为复杂:低温时,推进剂的εm和εb与lnν呈二次方关系,并随t的上升,先上升后下降;高温时,推进剂的εm和εb与lnν呈线性关系,随t的上升显著下降。     

Catalytic bed slenderness ratio and ADN/methanol ratio for decomposition and combustion characteristics within ammonium dinitramide(ADN)-based green aerospace thruster

The decomposition and combustion characteristics of ammonium dinitramide(ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure(slenderness ratio) and operation parameters(mass fraction ratio of ADN/CH_3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure–mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed with a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance.These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.     

Combustion of GAP/HMX and GAP/TAGN Energetic Composite Materials

Energetic composite materials (ECM) have high thermodynamic potential and flexible design capability. Two types of ECM were formulated as mixtures of glycidyl azide polymer (GAP) and crystalline materials. The crystalline materials evaluated were cyclotetramethylene tetranitramine (HMX) and triaminoguanidine nitrate (TAGN). The thermochemical properties of HMX and TAGN were different to each other: HMX is a high energy material but the burning rate is lower than that of TAGN. TAGN produces hydrogen as a combustion product and the thermodynamic potential becomes high even though the flame temperature is low. The results of burning rate measurement tests indicate that the burning rates of both ECM are decreased significantly by the addition of HMX and TAGN even though the burning rates of GAP, HMX, and TAGN are higher than those of the ECM. The temperature sensitivity of burning rate of GAP is reduced significantly by the addition of HMX and remains unchanged by the addition of TAGN. The reduced burning rates of GAP/HMX and GAP/TAGN are caused by the reduced heat flux transferred back from the gas phase to the burning surface. The reduced heat release at the burning surface of GAP/HMX is responsible for the reduced temperature sensitivity.     

Numerical simulation of transients in the ignition of two-component propellants by intense heat fluxes

An ignition model is developed for quasi-homogeneous propellants consisting of two perfectly mixed compnents which decompose independently in the condensed phase and then react in the gas phase. The model describes the heat propagation in the condensed and gas phases as well as the diffusion of components in the gas phase. The transition processes from ignition to self-sustaining combustion under pulsed irradiation are studied numerically for the simplest case of a monopropellant. It is shown that the critical value of heat flux for stable ignition of monopropellant and the shape of the stable ignition peninsula in the exposure time-heat flux coordinates depend on the extinction criterion.Tomsk. Novosibirsk. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 3, pp. 16–20, May–June, 1993.